I feel like I've seen the episode I just don't remember the name, If I do I'll let u know.

Ok, thanks ^^

I believe the episode is "evil mascot" from the 5'th season but i am not 100% sure

Can you check just to make sure EEEfox?

Its not not the eipsode The Fugitives, that cowboy outfit alex used is from episode Mime World (Jazz Hand's Return - Part 3)

As for mermaid outfit, its from season 5 episode Evil Mascot

@Uwwuuuuuu i checked the Mime World (Jazz Hand's Return - Part 3) episode, I didn’t see Alex wearing it there. Are you sure it was that episode?

Well, i did watch 3-Part of Jazz Hands Arc on youtube and I found it at 1:33

@Uwwuuuuuu ok, found it now, thank you ^^

Search it on YouTube and rewatch that episode yourself